Genetic Polymorphisms of Superoxide Dismutase 1 and Its Relationship to Diabetic Neuropathy and Nephropathy in Patients with Type 2 Diabetes Mellitus in Ahvaz, Iran

Diabetes is the most prevalent non-infectious disorder of endocrine glands with an increasing rate of incidence. Several people with this type of disease suffer from diabetic retinopathy and nephropathy. Oxidative stress is involved in the path physiology of diabetic nephropathy and retinopathy. The superoxide dismutase (SOD) enzymes play a major role in detoxification of reactive oxygen species and have a protective effect against diabetic nephropathy and retinopathy. Several studies claimed that the polymorphisms of this gene have a key-role in tissue damage results from diabetes. In the present study, two SNPs in SOD1 gene were analyzed in 145 patients with type 2 diabetes mellitus in Ahvaz, Iran. Blood samples of the patients and 145 individuals without diabetes as controls were collected. DNA was extracted and the polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) was performed. For the rs2070424 polymorphism, there were significant differences between the patients who suffer from nephropathy and the control group (P = 0.005; χ2 = 7.55); but no significant difference in the rate of this gene polymorphism between the patients with retinopathy and the control group was seen. The analysis of rs2234694 polymorphism showed that all individuals with and without diabetes had AA genotype. Therefore, it was impossible to perform any statistical test to determine the relationship of this polymorphism and diabetic nephropathy or retinopathy. Understanding the role of polymorphisms of SOD1 gene to modify the course of retinopathy could be an important target for future pharmacological interventions.